比较C中的两个字符串？ [英] Comparing two strings in C?

问题描述

此代码无效，未进行比较。为什么？所有名称都通过如果。

This code is not working, the comparison is not being done. Why? All names get past the if.

printf("Enter Product: \n");
scanf("%s", &nameIt2);
printf("Enter Description: \n");
scanf("%s", &descriptionI);
printf("Enter Quantity: \n");
scanf("%d", &qtyI);
printf("Enter Order Quantity: \n");
scanf("%s", &ordqtyI);

while(fscanf(fp4, "%s %s %d %s\n", &namet2,&description2,&qty2,&ordqty2) != EOF){
    if(namet2 != nameIt2)
        fprintf(fpt2, "%s %s %d %s\n", &namet2, &description2, qty2, &ordqty2);
}

推荐答案

要比较两个C字符串 char * ），请使用 strcmp（） 。当字符串相等时，函数返回 0 ，因此您的代码中需要这样：

To compare two C strings (char *), use strcmp(). The function returns 0 when the strings are equals, so you would need to this in your code:

if(strcmp(namet2, nameIt2) != 0)

（错误）使用

if(namet2 != nameIt2)

你正在比较两个字符串的指针（地址），当你有两个不同的指针（这在你的情况总是这样）是不相等的。

You are comparing the pointers (addresses) of both strings, which are unequal when you have 2 different pointers (which is always the case in your situation).

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