function reverse(str){
    let output = ""
    for(let i = stirng.length - 1; i >= 0; i--){
        output += str[i]
    }
    return output
}

function containsChar(haystack, needle){
    for(let i = 0; i < haystack.length; i++){
        let currentCharacter = haystack[i]
        if(currentCharacter == needle){
            return true
        }
    }
    return false
}

function indexOfChar(haystack, needle){
    for(let i = 0; i < haystack.length; i++){
        let currentCharacter = haystack[i]
        if(currentCharacter == needle){
            return i
        }
    }
    return -1
}


function removeChar(str, char){
    let output = ""
    for(let i = 0; i < str.length; i++){
        let currentCharacter = str[i]
        if(currentCharacter != char){
            output += currentCharacter
        }
    }
    return output
}

function replaceChar(str, char){
    let output = ""
    for(let i = 0; i < str.length; i++){
        let currentCharacter = str[i]
        if(currentCharacter != char){
            output += currentCharacter
        }else{
            output += char
        }
    }
    return output
}

function substring(str, start, stop){
    let output = "";
    for(let i = start; i < stop; i++){
        output += str[i]
    }
    return output
}

function contains(haystack, needle){
    for(let i = 0; i < haystack.length; i++){
        let match = true

        for(let j = 0; j < needle.length; j++){
            let haystackCharacter = haystack[i+j]
            let needleCharacter = needle[j]

            if(haystackCharacter != needleCharacter){
                match = false;
                break;
            }
        }

        if(match){
            return true
        }
    }
    return false;
}

function contains(haystack, needle){
    for(let i = 0; i < haystack.length; i++){
        let haystackString = substring(haystack, i, i+needle.length)
        if(haystackString == needle){
            return true
        }
    }
    return false;
}

function remove(haystack, needle){
    let output = ""
    for(let i = 0; i < haystack.length; i++){
        let match = true

        for(let j = 0; j < needle.length; j++){
            let haystackCharacter = haystack[i+j]
            let needleCharacter = needle[j]

            if(haystackCharacter != needleCharacter){
                match = false;
                break;
            }
        }

        if(match){
            i += needle.length-1
        }else{
            output += haystack[i]
        }
    }
    return output
}

function remove(haystack, needle){
    let output = ""
    for(let i = 0; i < haystack.length; i++){
        let haystackSubstring = substring(haystack, i, i + needle.length - 1)

        if(haystackSubstring == needle){
            i += needle.length-1
        }else{
            output += haystack[i]
        }
    }
    return output
}

function replace(haystack, needle, replaceWith){
    let output = ""
    for(let i = 0; i < haystack.length; i++){
        let match = true

        for(let j = 0; j < needle.length; j++){
            let haystackCharacter = haystack[i+j]
            let needleCharacter = needle[j]

            if(haystackCharacter != needleCharacter){
                match = false;
                break;
            }
        }

        if(match){
            i += needle.length-1
            output += replaceWith
        }else{
            output += haystack[i]
        }
    }
    return output
}