68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#define MAXVALS 4
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int main(void){
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// allocate space for a float on the heap,
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// return a pointer to it,
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// cast it to a float* ,
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// store it in f;
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float* pf = (float*) malloc( sizeof(float) );
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if(pf == (float*)NULL){
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fprintf(stderr, "Memory allocation failed. Program terminating.");
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return EXIT_FAILURE;
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}
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printf("Please enter a float value: ");
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scanf("%f",pf); // pf is a pointer, with space allocated to it
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printf("%f it is!\n", *pf);
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free(pf); // all done with fp
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// allocate space for an integer [] that hold MAXVALS ints on the heap,
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// return a pointer to it, cast the void* to a int* , and store it in arr;
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int iErr;
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int* arr = (int*) malloc( sizeof(int)*MAXVALS );
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if(arr == (int*)NULL){
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fprintf(stderr, "Memory allocation failed. Program terminating.");
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return EXIT_FAILURE;
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}
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printf("Please enter %d integer values: ", MAXVALS);
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for(int i=0; i<MAXVALS; i++){
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iErr = scanf("%d",&arr[i]); // arr is a pointer, with space allocated
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if(iErr != 1){
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fprintf(stderr, "Read failed. Program terminating.");
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free(arr);
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return EXIT_FAILURE;
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}
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printf("%d it is!\n", arr[i]);
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}
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free(arr); //all done with arr
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// allocate space for an char [] of that hold MAXVALS chars on the heap
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// (with room for the NULL), return a pointer to it, cast it to a char* ,
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// and store it in s.
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// Note that although s isn't YET a string, that's the intention.
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char* s = (char*) malloc( sizeof(char)*(MAXVALS+1) );
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if(pf == (float*)NULL){
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fprintf(stderr, "Memory allocation failed. Program terminating.");
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return EXIT_FAILURE;
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}
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printf("Enter up to four characters: ");
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getchar(); // flushes newline feed from last response
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char c = getchar();
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int i = 0;
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while(c != '\n' && i < MAXVALS){ // leave room for the terminating NULL!
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s[i] = c;
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i++;
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c = getchar();
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}
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s[i] = (char) NULL; // terminate the string
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printf("%s it is!\n", s);
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free(s); // all done with s
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return EXIT_SUCCESS;
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}
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