59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
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/* bigInt.c
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*
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* Demonstrates use of passing an array to a function.
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*
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* Also shows why sizeof() is not a reliable way to discover array size. It
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* *only* works correctly inside the function it's declared in. When passed
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* to a function, the *address* of teh begining of the array is passed and so
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* sizeof() returns the sizeof an address. Here's the compiler output
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* (I ignored the compile warnings to run it)
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*
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* wightman% gcc bigInt.c
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* bigInt.c:32:49: warning: sizeof on array function parameter will return size of
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* 'int *' instead of 'int []' [-Wsizeof-array-argument]
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* printf("bigInt: sizeof(a): %lu bytes\n", sizeof(arr));
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* ^
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* bigInt.c:29:16: note: declared here
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* int bigInt(int arr[], int iNarr){
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* ^
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* 1 warning generated.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#define N 5
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int bigInt(int arr[], int iNarr);
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int main()
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{
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int i;
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int iErr;
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int a[5];
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// sizeof() return a long unsigned int (%lu)
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printf("main: sizeof(a): %lu bytes\n", sizeof(a));
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printf("enter some integers,followed by ^D on blank line: ");
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i = 0;
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iErr = 1;
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while( iErr != 0 && i < N ){
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iErr = scanf("%d",&a[i]);
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i++;
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}
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printf("Biggest value: %d\n", bigInt(a,N));
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return EXIT_SUCCESS;
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}
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int bigInt(int arr[], int iNarr){
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int i;
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int big = arr[0];
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printf("bigInt: sizeof(a): %lu bytes\n", sizeof(arr));
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for(i=1; i<iNarr; i++){
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if(arr[i] > big)
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big = arr[i];
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}
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return big;
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}
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