#include "stdio.h" #include "string.h" // #define diff int main(){ int count = 0; char str[1010] = {0}; fgets(str,sizeof(str),stdin); // printf("%c",str[0]); char C = {0}; // printf("请输入一个字符:"); scanf("%c",&C); C = tolower(C); for(int i = 0; i<strlen(str);i++){ str[i] = tolower(str[i]...