题解 | #计算某字母出现次数#

const str = readline()
const chart = readline()
function getChartLen(str, chart) {
    if(!str || chart === null || chart === undefined){
        return 0
    }
    let strLen = str.length
    let len = 0
    str = str.toLowerCase()
    chart = chart.toLowerCase()
    for(let i = 0; i < strLen; i++) {
        if(str[i] === chart) {
            len++
        }
    }
    return len
}
console.log(getChartLen(str, chart))