c - 我的程序在关闭前不会运行我的 while 循环

Question

所以我的程序中没有语法错误，这是一个逻辑错误。我的问题是，当我尝试运行它时，只有我的 printf 语句会执行，但之后它关闭了我的程序，不允许我的 while 循环 请求更多数据，直到用户输入-1 停止我的 while 循环。

#include <stdio.h>
// prototypes
void updateLevel(int PlayerPoints, int playerLevels[]);
void displayLevels(int ArrayName[]);

//main begins
int
main (void){
    //arrays and varibles
    int playerLevels[6] = {0};
    int playerPoints = 0;

    printf("Player points (-1 to quit) ");
    scanf("%d" , &playerPoints);
    //while loop to process input data
    while(playerPoints =! -1){
        scanf("Player points (-1 to quit)  %d" , &playerPoints);
        updateLevel(playerPoints, playerLevels);
    }

    displayLevels(playerLevels);
    return(0);
}
//main ends

//functions
void updateLevel(int playerPoints, int playerLevels[]){
    if(playerPoints >=50)
    playerLevels[6]++;
    else if (playerPoints >=40)
        playerLevels[5]++;
    else if (playerPoints >= 30)
        playerLevels[4]++;
    else if (playerPoints >= 20)
        playerLevels[3]++;
    else if (playerPoints >= 10)
        playerLevels[2]++;
    else
        playerLevels[1]++;

}

void displayLevels(int playerLevels[]){
    printf("T O T A L S\n");
    printf("Level 1    %d\n", playerLevels[1]);
    printf("Level 2    %d\n", playerLevels[2]);
    printf("Level 3    %d\n", playerLevels[3]);
    printf("Level 4    %d\n", playerLevels[4]);
    printf("Level 5    %d\n", playerLevels[5]);
    printf("Level 6    %d\n", playerLevels[6]);
}

Answer 1

对于初学者而不是这个

while(playerPoints =! -1){
                   ^^

必须有

while(playerPoints != -1){
                   ^^

原语句等同于

while(playerPoints = 0){

所以循环没有执行。

但是程序有未定义的行为，因为你定义了一个包含 6 个元素的数组

int playerLevels[6] = {0};

但是你正试图访问数组之外​​的内存

if(playerPoints >=50)
playerLevels[6]++;

数组索引的有效范围是[0, 5]索引从0开始。